We propose the continued follow-up in the year 2000 of the sample studied between 1994 and 1996 for the National Longitudinal Study of Adolescent Health. At that time respondents will be 18-24 years of age, and all out of high school. The primary purpose of the continued follow-up is to determine the later health effects of adolescence as our sample moves into young adulthood. The project s long-term goal is to provide the research community with a public use data set that, when linked to existing Add Health data set now in the public domain, will provide a powerful scientific tool for the study of health transitions in adolescence and young adulthood. We propose a set of sub- projects on STD and HIV acquisition, binge drinking, romantic relationships, sexual networks, obesity, non-marital childbearing, and resilience/vulnerability. Behavior-genetic analysis of health risk is proposed both as a sub-project and a method shared by other sub-projects.